I tried to put it into /etc/local.rc and I tried to put it into the startup programs, but nothing worked. It is strange: right after boot, the three finger tap works, but after about 10 seconds it seems to be reset.

Maybe when you log in? As you're unlikely to need it before. Add it to the startup applications?
– TimAug 31 '14 at 20:51

I would be interested in a delayed command like that, I guess I could just write a script with a sleep 20 + the load, because my Gnome Terminal is never opened at the right place (namely, never on the right desktop, I have 4, and nearly never at the right location.) I blame that on loading the terminal too soon, before the desktop is set to its final size by the video driver...
– Alexis WilkeAug 31 '14 at 21:07

@Glutanimate I can imagine the comparison, but there is a subtle, but important difference: in that question, it is about a delayed start of an application, with a .desktop file, and so are most of the answers. This is about running a single command after x time.
– Jacob VlijmSep 1 '14 at 12:39

1

@Glutanimate also true of course, but the accepted solution here does not elegantly fit the other question, and just using Startup Applications is in this case less work then first creating, then editing the .desktop file I think. But even if that were not the case, possible solutions do not necessarily match. But as said, I can understand the comparison.
– Jacob VlijmSep 1 '14 at 15:38